Even if you have Autogen slider all the way to the left and have the Traffic set to 0. you end up with a big FPS drop flying around big cities compared to flying in rural areas.I know, even with autogens set to 0, there are a few buildings (downtown). But are those few tall buildings the cause for such a FPS drop?Any ideas why?Manny

Those buildings may be scenery objects, as opposed to autogen....and yes, they can cause a drop in FPS. There is a slider for those as well.

You may be seeing just a few big buildings in a city, but many of them are quite detailed with hundreds of polygons compared to just a dozen or two for an autogen object, and more importantly those skyscrapers have massive textures attached to them, with bump and specular maps. Each of those ends up being equivalent to the rendering cost of a large number of autogen objects.

Frankly,I think the autogen engine is broken. It was a problem in FS9 before the patch and it looks like it's still there. I use "sparse" and the .cfg tweak to reduce trees and buildings. It doesn't matter how low I put them, if autogen is "on" there is a hit to framerates (granted the hit is pretty mild at very low autogen settings, but it is still there).Randall

Correct, the "scenery complexity" slider. Scenery objects like city buildings, bridges, and animated flocks of birds consume significant CPU time.